1. Field of the Invention
The present invention relates to a three-dimensional image communication terminal which can make communication in which there are sense of being engaged on a place and sense of reality by use of a three-dimensional image with naturalness and a high robust characteristic.
2. Description of the Related Art
As a representative example of a conventional image communication terminal, there was a TV phone. The TV phone is generally configured by an image input section having a camera which shoots a telephone calling person, an image display section which monitor-displays a telephone calling person image which was shot, and a conventional telephone calling section which transmits/receives this image information and communicates by voice. In a conventional TV phone, as means of inputting an image of a telephone calling person, transmission/reception by use of a two-dimensional image was commonly used, but a two-dimensional image is poor in depth sense and it was difficult to obtain such sense of being engaged on a place and such sense of reality that an actual partner exists right over there and is making communication. In addition, if an object, which appears in communication, is intended to be displayed as an image to a partner with whom communication is made, with sense of being engaged on a place, two-dimensional display is poor in sense of being engaged on a place and sense of reality.
From long ago, as means of displaying three-dimensional image information, there are a naked eye hypostatizing parallel method in which, as to two pieces of pictures, which include binocular disparity, a right image is viewed by a right eye and a left image is viewed by a left eye, a stereo scope of viewing by use of eyeglasses with a liquid crystal shutter and lenses which are different for a right eye and a left eye respectively, and an anaglyph system in which an image of a binocular disparity picture with different colors of red and blue is viewed through red and blue glasses. However, in case of viewing a three-dimensional image by these methods, particular eyeglasses and training were necessary.
In recent years, due to development of liquid crystal technologies, liquid crystal displays, which are capable of three-dimensional display without necessity of glasses, have been made public, one right after the other. Most of them are image splitter type three-dimensional liquid crystal display devices with no glasses, so-called parallax barrier type and lenticular lens type three-dimensional image display devices having only horizontal parallax. In the parallax barrier type and the lenticular lens type three-dimensional display devices, a three dimensional effect is generated by separating and supplying image optical paths spatially, in order to be able to view a right eye image from a right eye position and to view a left eye image from a left eye position. Therefore, image optical paths are separated and supplied to a right eye position and a left eye position spatially and periodically, and when the positions are misaligned, a three-dimensional figure is broken down. Since images including parallax in a horizontal direction are supplied as a fundamental principle, there is such a problem that a three-dimensional figure is broken down, when a right eye position and a left eye position are misaligned from a horizontal line. Therefore, when it is tried to carry out stereoscopic viewing for a long time with keeping a three-dimensional figure of a three-dimensional moving image, there is need to fix a right eye position and a left eye position to fixed positions in a space. However, this becomes an important problem for long hour communication. In addition, in such a system that a two-dimensional image exists in reality but nevertheless, a difference of parallax, which is included in left and right images, is converted into a three-dimensional image in a brain through a retina and it is recognized, eye fatigue is intensive and it is not suitable as long-term communication means, which is one of big problems.
Against misalignment of a right eye position and a left eye position in a horizontal direction, a method of controlling and correcting image optical paths in tune with the misalignment of positions, by specifying positions of eyes and a position of a face of a viewing person has been invented, but there occurs such burdens that a device becomes a large scale and a marker must be attached to a viewing person for sensing positions of eyes and a position of a face.
As a prior art document regarding a three-dimensional TV phone, there is, for example, JP-A-10-75432 publication.